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Olympic Coaching by Computer.

by Ken Sheldon

The high-diver stands in mute concentration, poised for the jump that could mean a gold medal in the upcoming Olympic games. After a few seconds of intense mental preparation, she springs, arches and completes a flawless dive-right off the computer screen. The diver is a computerized stick-figure, recreating a dive made by a real championship diver hours earlier, in a technique developed by Dr. Gideon Ariel, Chairman of the Biomechanics and Computer Science committee of the US Olympic Team.

"What we have developed is the most advanced system in the world for improving athletic performance using state-of-the-art high technology," Ariel says. The system, known as "biomechanical analysis," makes use of high-speed cinematography of athletic performances, sometimes filming as many as 400 or 500 frames per second. In the laboratory, each frame of the film is "digitized," using a kind of electronic tracing device that sends the X,Y coordinates of each of the athlete's major joints to a set of Apple II computers, the real workhorses of the system.

"The Apple is fantastic as an intelligent storage device," says Ariel. "We use Data General minicomputers to do the actual calculations on the raw data, but because the process of digitizing takes hours and hours, there is no reason to start up the minicomputers, which are very big and very power-consuming. Instead, we use the Apples to collect the information and store it on floppy disks. Then, after three or four hours of digitizing, we use a transfer program to dump the data into the minicomputer, which does the. actual calculations."

The minicomputer, a Data General Eclipse, essentially plays dot-to-dot with the data, connecting the points and creating a cartoon-like representation of the athlete's performance with the help of a $100,000 CAD/CAM graphics system from Megatech of San Diego. "We can then use the computer's three-dimensional capabilities to rotate the image and look at it from the top, the side, or whatever angle we want," says Dr. Ariel.

The computer also performs calculations on the data that provide insights into the athlete's performance. "We can tell what the person's range of motion is, how fast he or she is moving, what is the acceleration-and based on that we can calculate the efficiency of their movements." Dr. Ariel notes that, although the eight-bit Apples do not have the power to do this kind of analysis, "I'm sure that you could do the same thing with the 32-bit Lisa or Macintosh." In fact, one of" the projects that Ariel is most excited about these days is transferring his system to microcomputers. "With the advent of personal computers, we can now emulate the equipment that cost us $2

million to assemble in our labora

tory for a total cost of under

$15,000," says Ariel.

"That's still not cheap, but in the

very near fu

ture, every

serious coach or club might be able to afford such a system."

The real essence of biomechanical analysis is the system's software, written by Dr. Ariel and a dozen other people, which converts the millions of bits of raw data collected from the films into information on the velocity, acceleration and momentum of each of the athlete's joints during each phase of his or her performance-information that almost always leads to improved performance, according to Ariel. "Even though an athlete is of worldclass caliber, you' always find out that they have a lot of errors," he notes.

A good example of the kind of improvement possible through biomechanical analysis is 45-year-old Al Oerter, who threw the discus and won four gold medals during the 1960s. "When we contacted Oerter in 1980, people laughed because they thought he was too old to compete again," Ariel says. "We found out, however, that we could improve his technique to the point that, at the age of 45, he was throwing his best ever. In fact, the last time he was at our lab, he threw the discus over 240 feet, which is beyond the world record."

In addition to high-speed cinematography, Ariel's system also includes the use of a sophisticated "force platform" that contains thousands of weight-sensitive sensors. As athletes perform on the board, the sensors transmit information about the athlete's stance, weight placement, balance and movement to the computers. "The device is so sensitive," claims Ariel, "that I could read your pulse just from the

motion of your body as you stand on it." Such pinpoint sensitivity has led Ariel to some amazing discoveries. For example, the world's best archers are those who release their arrows between heartbeats. "They didn't even know they were doing this," Ariel says. "But it makes sense, because the body is the most stable between heartbeats and even the slightest movement can affect the course of the arrow."

Since helping to establish the US Olympic Committee's sports medicine laboratory in Colorado Springs, Dr. Ariel has opened his own private research center in Coto de Caza, California. Coaches and athletes still seek him out, and the variety of sports to which his method of biomechanical' analysis has been applied seems to amaze even himself.

"We now have data in our memory banks on probably 10,000 different athletes," he says. "We've dealt with just about every kind of sport that you can imagine." Sprinters such as Evelyn Asherude, hurdlers such as Edwin Moses, high divers such as Greg Laginus, golfers, swimmers, divers, shotputters, javelin-throwers, and even figure skaters have been helped by his methods. "We found, for example, that if a figure skater's trunk is wobbling, he or she will usually receive a lower score," Ariel says. "If the trunk is stable, the performance appears more pleasing to the eye. So, this becomes something for the coach and the skater to work on."

Individual athletes are not the only ones who have been helped by Dr. Ariel, The most recent beneficiaries of

his expertise are the members of the US women's volleyball team. "When we started with them, they were about 50th in the world," Ariel says. "But we have developed a technique that can detect all kinds of trends in the play of the opposing teams. What we did was to analyze high-speed films of teams like the Chinese, Japanese and Bulgarians in championship matches such as the World Cup and other international meets." By computer analysis of the other teams, Ariel has been able to predict within one or two feet where their players will be at any given time-and, more importantly, where they will not be, in the event of a spiked volleyball in that part of the court. The result, according to Ariel, is that the US players are now beating teams that they couldn't before. "It's like playing poker with somebody when you know all the cards that they have," he says.

Nor are humans the only ones that Ariel has helped with his system. "We have worked with some very famous racehorses, the most famous of which was Spectacular Bid," says Ariel, although he notes that the horses and owners that have benefited most from his work are those with less-than-spectacular performances. "You can make more money betting on bad horses, since the odds on a bad horse are much better than the odds on a good horse. If you can train a bad horse to do well two or three times-well, some of the owners made millions of dollars on

Ken Sheldon is the news editor for jr. magazine. Write to him at 80 Pine St., Peterborough, NH 03458.

April 1984 Cider 37

An uthh is tï¿½r.s his isometric grip with Gideon Ariel's computerized exereiu nuu'hinrï¿½.

Digitized information on the locations of Olympic volleyball players could net them victories in future meets.

e those ventures," he notes. He adds that the beauty of working with horses rather than human athletes is that "they don't talk back."

Dr. Ariel's work has a lighter side. "We worked with one MIT student who wanted to break the world record in throwing the Frisbee," he recalls. "He was crazy about the Frisbee." Ariel's team did an analysis of the student's repertoire of throwing styles and, sure enough, the ambitious Frisbee tosser did indeed go on to break the world record.

Gideon Ariel was an Olympic contender himself, tossing the discus in the 1960 and 1964 Olympics. That, along with a Ph.D.. in computer science, led

him to, as he puts it, "combine Rocky with Star Wars," and pioneer the science of biomechanical analysis.

One of Ariel's first moneymakers was the principle behind the popular universal gym. "I patented the variable resistance mechanism, which was very profitable for us, since we got royalties from every universal gym machine in the world," he says. Later, Ariel helped with the development of the Nautilus weight-training machines, at which point he began to realize that, in the future, exercise machines would be computer-dependent, rather than gravity-dependent as in the past. At Coto de Ca7a, Ariel's team developed what he calls the next gen

eration in exercise equipment, the computerized exercise machine. "There are no weights in it at all," he explains. "The resistance is supplied by a hydraulic mechanism that is controlled by computer." The system, which is built around a Motorola 6509 microprocessor, senses the motion of the person exercising and decides the optimum amount of resistance to provide in order to reach certain levels of achievement. Not only have a number of professional sports teams such as the Dallas Cowboys, the New England Patriots and the Denver Broncos purchased Ariel's computerized exercise machines, but they are finding widespread usage in hospitals and research

After performing sophisticated calculations on information fed from the digitizer, Ariel's system products animated graphic images such as this one of a hurdler in action.

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centers such as the Harvard Medical School, where they are proving to be ideal for rehabilitation work with the handicapped and those recovering from surgery or accidents.

These days, Ariel's team is turning its sights to a host of new and commercial projects, such as using computers to design the perfect tennis racket or golf club. Another project involves an inflatable shoe. "We think that, in the future, running shoes, as in the tire industry, will be inflatable," he says. "With an inflatable shoe, you can make it fit the foot exactly, using little air bladders that you inflate." Sound crazy? Not to the Japanese company that for a few years paid Ariel royalties not to make the shoes, for fear of what it would do to their business, nor to the major manufacturer of athletic shoes with which he now has a confidential contract to develop the shoes.

And if inflatable shoes are not futuristic enough, imagine this: Ariel hopes to use laser technology to project holograms of athletes in action. "Let's say we want bur women's volleyball team to play against the Chinese team. There is no reason why we couldn't create a holographic representation of that team and actually have our team `play against them," says Ariel.

Such are the kinds of dreams that keep things hopping at Gideon Ariel's laboratory. For now, however, he is most excited about transferring his method of digitized biomechanical analysis to personal computers. "In the future, every coach will be able to have a microcomputer on his desk to analyze his team," he says. "And someday, parents may even be able to have this kind of system at home and be able to do digitization right from their televisions. Then they will be able to tell whether their children are cut out to be basketball players, sprinters, or even piano players." And why not? Olympic contenders are starting to train younger and younger these days. Why not begin at home, with the help of Mom, Dad, and the newest members of the family-a home computer, a high :speed digitizer and a force platform or two?

Dr. Ariel, where were you when I was trying to learn how to play basketball? E

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